cpufreq: use separate user_min/user_max

user_min/user_max is not touched by kernel-space such as thermal throttling.
These are used for big CPU initialization in our case.
These replaces scaling_min_freq/scaling_max_freq and old policy->min/max are
moved to policy_min_freq/policy_max_freq.
Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>

Adapted by Alexander Alexeev <alexax66@gmail.com>

Based on commit https://bitbucket.org/arter97/android_kernel_samsung_exynos7420/commits/992e63bb0e5529104f3e5b0fd5cf2ef3fb309f6a